The role of surveillance imaging for resected high-risk melanoma.

Background: Recommendations for surveillance imaging for resected melanoma vary considerably. This study examined the utility of imaging in patients with a high-risk primary melanoma undergoing a protocolized imaging schedule.

Methods: This retrospective study involved data collection regarding imaging, recurrence, and outcome characteristics for patients referred to the Victorian Melanoma Service from January 2016-April 2020 and managed for resected stage IIC or III melanoma. Patients with a T4b tumor who did not undergo a sentinel lymph node biopsy were included (T4bNX). Recurrences were "clinically detected" if they were primarily detected by patient symptoms or physical examination, or 'imaging-detected' if the patient was asymptomatic. Cox regression models including time-varying co-variates were used to assess the impact of imaging-detected versus clinically-detected recurrence on overall survival.

Results: Over a median follow-up time of 2.7 years, 199 patients underwent surveillance imaging (T4bNX:22, IIC:33, IIIA:22, IIIB:60, IIIC:61, IIID:1), and 44% (n = 88) experienced disease recurrence. Imaging detected over half (53%) of all recurrences. In adjusted analyses, mortality risk was reduced after an imaging-detected compared to clinically-detected recurrence at any given time from the start of surveillance (hazard ratio 0.25, 95% confidence interval 0.10-0.66, p = .005).

Conclusion: Our study indicates that routine imaging in the early follow-up period of resected T4bNX, stage IIC and III melanoma plays an important role in the detection of asymptomatic recurrences. Imaging-detected recurrence may be associated with a survival benefit and studies with more prolonged follow-up are required to confirm these findings.